This is a note to let you know that I've just added the patch titled NFS: Fix up commit deadlocks to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: nfs-fix-up-commit-deadlocks.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 0c927559b26c95d666de47401bda311e5c86d290 Author: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> Date: Mon Oct 4 15:37:42 2021 -0400 NFS: Fix up commit deadlocks [ Upstream commit 133a48abf6ecc535d7eddc6da1c3e4c972445882 ] If O_DIRECT bumps the commit_info rpcs_out field, then that could lead to fsync() hangs. The fix is to ensure that O_DIRECT calls nfs_commit_end(). Fixes: 723c921e7dfc ("sched/wait, fs/nfs: Convert wait_on_atomic_t() usage to the new wait_var_event() API") Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c index 2e894fec036b0..3c0335c15a730 100644 --- a/fs/nfs/direct.c +++ b/fs/nfs/direct.c @@ -620,7 +620,7 @@ static void nfs_direct_commit_complete(struct nfs_commit_data *data) nfs_unlock_and_release_request(req); } - if (atomic_dec_and_test(&cinfo.mds->rpcs_out)) + if (nfs_commit_end(cinfo.mds)) nfs_direct_write_complete(dreq); } diff --git a/fs/nfs/pnfs_nfs.c b/fs/nfs/pnfs_nfs.c index 37b52b53a7e53..7b9d701bef016 100644 --- a/fs/nfs/pnfs_nfs.c +++ b/fs/nfs/pnfs_nfs.c @@ -468,7 +468,6 @@ pnfs_bucket_alloc_ds_commits(struct list_head *list, goto out_error; data->ds_commit_index = i; list_add_tail(&data->list, list); - atomic_inc(&cinfo->mds->rpcs_out); nreq++; } mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex); @@ -520,7 +519,6 @@ pnfs_generic_commit_pagelist(struct inode *inode, struct list_head *mds_pages, data->ds_commit_index = -1; list_splice_init(mds_pages, &data->pages); list_add_tail(&data->list, &list); - atomic_inc(&cinfo->mds->rpcs_out); nreq++; } diff --git a/fs/nfs/write.c b/fs/nfs/write.c index dc7201c83bc29..bde4c362841f0 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -1649,10 +1649,13 @@ static void nfs_commit_begin(struct nfs_mds_commit_info *cinfo) atomic_inc(&cinfo->rpcs_out); } -static void nfs_commit_end(struct nfs_mds_commit_info *cinfo) +bool nfs_commit_end(struct nfs_mds_commit_info *cinfo) { - if (atomic_dec_and_test(&cinfo->rpcs_out)) + if (atomic_dec_and_test(&cinfo->rpcs_out)) { wake_up_var(&cinfo->rpcs_out); + return true; + } + return false; } void nfs_commitdata_release(struct nfs_commit_data *data) @@ -1752,6 +1755,7 @@ void nfs_init_commit(struct nfs_commit_data *data, data->res.fattr = &data->fattr; data->res.verf = &data->verf; nfs_fattr_init(&data->fattr); + nfs_commit_begin(cinfo->mds); } EXPORT_SYMBOL_GPL(nfs_init_commit); @@ -1797,7 +1801,6 @@ nfs_commit_list(struct inode *inode, struct list_head *head, int how, /* Set up the argument struct */ nfs_init_commit(data, head, NULL, cinfo); - atomic_inc(&cinfo->mds->rpcs_out); return nfs_initiate_commit(NFS_CLIENT(inode), data, NFS_PROTO(inode), data->mds_ops, how, RPC_TASK_CRED_NOREF); } diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h index 91a6525a98cb7..aff5cd382fef5 100644 --- a/include/linux/nfs_fs.h +++ b/include/linux/nfs_fs.h @@ -553,6 +553,7 @@ extern int nfs_wb_page_cancel(struct inode *inode, struct page* page); extern int nfs_commit_inode(struct inode *, int); extern struct nfs_commit_data *nfs_commitdata_alloc(bool never_fail); extern void nfs_commit_free(struct nfs_commit_data *data); +bool nfs_commit_end(struct nfs_mds_commit_info *cinfo); static inline int nfs_have_writebacks(struct inode *inode)